Lestee p



Nb Model.)

L. P. THOMPSON.

Plow.

No. 231,378. Patented Aug. 17,1880.

N.FEI'ER5. PHOTO-UTHOGRAPHER. WASHINGTON D C UNITED STATES PATENT OFFICE.

LESTER P. THOMPSON, OF PHELPS, NEW YORK.

PLOW.

SPECIFICATION forming part of Letters Patent No. 231,378, dated August 17, 1880.

' Application filed April 2, 1880. (No model.)

To all whom it may concern:

Be it known that I, LESTER P. THOMPSON, of Phelps, Ontario county, New York, have invented a certain new and useful lniprove ments in Plows; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, in which- Figure 1 is a side elevation of the moldboard of a plow,--sho\ving my improvement. Fig. 2 is a Vertical cross-section of a portion of the mold-board on an enlarged scale.

My improvement relates to mold-boards or other parts of the plow used in turning the furrow; and it consistsin chillingthe same in such a manner that alternate strips of chilled and unchilled surface shall extend longitudinally of the mold-board, or in the line of the passage of the furrow over the same, as hereinafter more fully described.

The drawings show a mold-board of ordinary form, in which the strips a a of the exterior surface represent the chilled portions, and the intermediate strips, 1) b, represent the unchilled portions, the same extending longitudinally, or at such angle that they shall lie in the line of passage of the furrow over the mold-board.

The chilled strips are preferably made some- What wider than the unchilled ones; but, if desired, they may be of the same width or narrower, as occasion requires.

The chilling is done. placing chills in the molds in the well-known way, the chills lying in lengths corresponding with the strips to be produced, and said chills being convenient-1y made in sections, fitted end to end. These alternate strips of chilled and unchilled surface may also be used on the landside, the point, and other parts of the wearing-surface subjected to the action of the earth in plowing. The chilled surface is hardened to considerable depth, while the unchilled surface is comparatively soft.

In use the unchilled strips will wear away the fastest, and in time will leave depressions or channels extending longitudinally sunken somewhat below the surface of the chilled strips, and this will allow passage of air and tend to lessen suction in turning the furrow, and thereby reduce the draft. By this means, also, all the advantages of a chilled surface over an unchilled one are attained, such as greater wear, a smoother surface, and less friction with the furrow, while the substantial advantages of an unchilled surface are also attained, such as greater strength than a whole chilled surface. In this case the unchilled strips, by communicating at the edges, form a skeleton of soft metal, which gives great strength, the chilled strips forming, as it were, bars inclosed in the soft-metal frame.

While all the advantage of a whole chilled surface is attained by thisimprovement, great expense is saved, since in a whole chilled surface an expensive pattern-chill has to be made. In this case the chill-strips are readily formed and adapted to the mold, and will endure much longer than a whole pattern.

Where a full-chill pattern is used there is also great warping and twisting of the casting, owing to the shrinkage, which in the use of these chill-strips is avoided.

Where the whole surface is chilled, iron of a superior quality is required to secure proper strength, while in this case a much inferior quality of iron can be used and attain the same or superior strength.

If desired, the chills may be so connected as to form one integral pattern, but separate strips are preferably used.

Having thus described my invention, what I claim as new is- A mold-board or other wearing part of a plow provided with alternate strips of chilled and unchilled surface extending longitudinally or in line with the passage of the soil over it in plowing, as specified.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

LESTER P. THOMPSON.

Witnesses R. F. Oseoon, A. I. HULETT. 

